Rare spider halts San Antonio road project

The spider in the picture is the same genus as the Braken Bat Cave meshweaver; because it's a juvenile, biologists can't determine if it's that specific species. However, the two spiders look identical.

More Information

The Braken Bat Cave meshweaver

Scientific name: Cicurina venii

First discovered: In 1980 in northwest Bexar County by George Veni, a hydro-geologist.

Protected: The spider was put on the federal endangered species list in 2000.

Characteristics: The adult spiders are about the size of a dime. They are not known to be venomous to humans.

SAN ANTONIO - An endangered species of spider not seen in more than three decades unexpectedly appeared in northwest San Antonio two weeks ago, showing up in the middle of a $15.1 million highway underpass project.

The highway project is now on hold indefinitely.

A biologist discovered the eyeless spider, called the Braken Bat Cave meshweaver, after rain exposed a 6-foot-deep natural hole in a highway median at Texas 151 and Loop 1604.

Construction, under way since April, was halted late last week after a taxonomist confirmed that the creature, no bigger than a dime, was indeed the endangered meshweaver. The spider, named for the type of web it spins, is not known to be venomous to humans. It was added to the federal endangered species list in 2000, along with eight other "karst invertebrates" found only in Bexar County.

Biologists have been working alongside construction crews from the start because the area is known for its abundance of natural resources, including songbirds and rare cave animals, like the spiders, said Stirling J. Robertson, biology team leader for the Texas Department of Transportation's environmental affairs division.

To find a Braken Bat Cave meshweaver was a discovery of another kind altogether, akin to "stumbling on a new Galapagos Island in terms of the biological significance of the region," said biologist Jean Krejca, president of Zara Environmental, a consultant for the Texas Department of Transportation.

Well-known hydro-geologist George Veni first identified the spider in 1980 in northwest Bexar County, about 5 miles from the construction site. The spider's genus species classification reflects its namesake: Cicurina venii.

But the cave where Veni found it was later filled, and now is covered by a residential development. The Braken Bat Cave meshweaver spider hadn't been seen since.

The entire area where the Braken Bat Cave meshweaver was found two weeks ago could be a spider habitat. Biologists have identified 19 cave features, which look like holes, while working on the underpass project.

About 80,000 vehicles a day traveled this intersection in 2010, according to TxDOT. For drivers, the spider could mean big delays in the completion of the underpass.

It was set to open by next summer.

Now, both federal agencies will re-evaluate the project until they can agree on a plan that doesn't disturb any spiders potentially living in the area, or the habitat where the creatures might be bedding down.